It is known that fluorochemicals, particularly certain fluorochemical copolymers, can be used to impart water, oil or grease repellency to paper and paper products, and to textile fibers such as nylon used in carpets and upholstered furniture. It is also known that certain fluorochemical copolymers can be used in combination with other substances to improve the resistance of construction materials to water and oil damage. For example JP 9286676 A teaches to employ an aqueous emulsion of a fluororesin which is a copolymer of a fluoro-olefin, a carboxylic acid vinyl ester and unsaturated monomers having hydrophilic functional groups with a water emulsion of a silane compound which has hydrolyzable functional groups to form a water-repellent, weather-resistant coating on the surface of cured concrete.
EP-A 0 714 921 teaches two component resin compositions for water-repellent coatings for textiles and building materials which comprise a fluorinated acrylic copolymer component which also contains cationic amino groups, either in salt or quaternized form, and other functional groups, and a polyisocyanate component. On mixing the two water-based components and applying the mixture to building materials, they harden rapidly to a coating which imparts stable water- and oil-repellent, anti-graffiti properties to the treated substrates.
U.S. Pat. No. 5,753,569 teaches a two component coating treatment to render substrates selected from the group consisting of naturally occurring and synthetic textiles and their mixtures, leather, mineral substances, thermoplastic and thermosetting polymers and paper, oil-, water- and soil-repellent by applying thereto compositions containing components A and B, wherein component B is a fluorine-free poly(meth)acrylate ester and component A is fluorine-containing and comprises repeating units from a) 40 to 85% by weight of (meth)acrylates containing perfluoroalkyl groups, b) 1 to 45% by weight of one or more monomers from the group consisting of styrene, acrylonitrile, vinyl acetate, vinyl propionate and (meth)acrylate esters, c) 4 to 30% by weight of (meth)acrylate esters of polyether polyols and d) 1 to 15% by weight of ionic or ionizable monomers which either contain an amine or a carboxyl function.
EP-A 0 714 870 teaches an oleophobic and hydrophobic treatment for construction materials which comprises applying to the surface of the materials to be treated a mixture of a water soluble cationic fluorinated acrylic copolymer of the type disclosed in U.S. Pat. No. 5,493,998 and a polymeric film former, polyvinyl alcohol. The copolymers are reaction products of a perfluoroalkylethyl acrylate, a dialkylalkylaminoethyl methacrylate, vinyl acetate and optionally a fourth monomer such as butyl methacrylate. While some protection can be provided by saturating a surface with an aqueous solution of the copolymer alone, the high concentration of the water-soluble cationic fluorinated acrylic copolymer required, 20-25%, makes this approach unattractive and impractical.
A disadvantage of all of the above surface treatments for a number of applications, whether they are cross-linked resins or physical mixtures with a polymeric film former, is that they form coatings which seal the surface of the construction material. This often results in an esthetically undesirable shiny and unnatural appearance. Additionally, a coating will normally make a surface more slippery and prevent water drainage. Both of these properties would be highly undesirable in a surface treatment for horizontal surfaces such as concrete floors, sidewalks, driveways, parking lots, roadways and airport runways for example.
It was therefore and object of this invention to find a one component surface treatment for calcitic and/or siliceous architectural and construction materials which was free of crosslinking agents and fluorine-free film-forming polymers which would not impart a shiny and unnatural appearance to the surfaces, and would not impair traction on treated horizontal surfaces.
It has now been found that calcitic and/or siliceous architectural and construction materials, such as bricks, tiles, marble, stone, plaster, concrete, cement and mortar, can be provided with increased resistance to damage from water, oil, grease and weather, while remaining porous and retaining a natural appearance, by treating them with a composition comprising a dilute aqueous solution or self-dispersed emulsion or dispersion of certain cationic, fluorinated copolymers, optionally in the presence of an effective amount of a penetration assistant.